scholarly journals Use of Neuroanatomic Knowledge and Neuronavigation System for a Safe Anterior Petrosectomy

2021 ◽  
Vol 11 (4) ◽  
pp. 488
Author(s):  
Ana Flores-Justa ◽  
Sabino Luzzi ◽  
Alice Giotta Lucifero ◽  
Juan F. Villalonga ◽  
Amparo Saenz ◽  
...  
Keyword(s):  
Anterior Part ◽  
Internal Auditory Canal ◽  
Petrous Bone ◽  
Surgical Approaches ◽  
Illustrative Case ◽  
Petroclival Region ◽  
Anterior Transpetrosal Approach ◽  
Neuronavigation System ◽  
Anterior Petrosectomy ◽  
Key Aspects

Introduction: The petroclival region is among the most challenging anatomical areas to deal with in skull base surgery. Drilling of the anterior part of the petrous bone during the anterior transpetrosal approach involves the risk of injury of the cochlea, superior semicircular canal, internal carotid artery, and internal auditory canal. A thorough understanding of the microneurosurgical anatomy of this region is mandatory to execute the transpetrosal approaches, decreasing the risk of complications. The aim of this study is to describe the anatomical structures of the petroclival region, highlighting the importance of neuronavigation for safe performance of the anterior transpetrosal approach. Methods: Three adult cadaveric human heads were formalin-fixed and injected with colored silicone. They underwent an axial 1 mm slab CT scan, which was used for neuronavigation during the surgical approaches. The anterior petrosectomy was performed with the aid of neuronavigation during the drilling of the petrous bone. The surgical management of a patient harboring a petroclival meningioma, operated on using an anterior transpetrosal approach, was reported as an illustrative case. Results: The anterior petrosectomy was completed accurately with wide exposure of the surgical target without injuring the cochlea and other structures in all three cadaveric specimens. In the surgical case, no approach-related complications occurred, and a gross total resection of the tumor was achieved. Conclusions: Deep knowledge of the location and relationships of the vital elements located within the temporal bone, along with the use of neuronavigation, are the key aspects to perform the anterior transpetrosal approach safely, reducing the risk of complications.

scholarly journals An aberrant venous channel mimicking the perilabyrinthine cells in the petrous bone of a patient with vestibular schwannoma: illustrative case

2021 ◽  
Vol 2 (18) ◽  
Author(s):  
Masato Ito ◽  
Yoshinori Higuchi ◽  
Kentaro Horiguchi ◽  
Shigeki Nakano ◽  
Shinichi Origuchi ◽  
...  
Keyword(s):  
Vestibular Schwannoma ◽  
Internal Auditory Canal ◽  
Posterior Wall ◽  
Anatomical Variations ◽  
Petrous Bone ◽  
Bone Defects ◽  
Jugular Bulb ◽  
Illustrative Case ◽  
Computed Tomographic ◽  
Major Vein

BACKGROUND Anatomical variations, such as high jugular bulbs and air cell development in the petrosal bone, should be evaluated before surgery. Most bone defects in the internal auditory canal (IAC) posterior wall are observed in the perilabyrinthine cells. An aberrant vascular structure passing through the petrous bone is rare. OBSERVATIONS A 48-year-old man presented with a right ear hearing disturbance. Magnetic resonance imaging revealed a 23-mm contrast-enhancing mass in the right cerebellopontine angle extending into the IAC, consistent with a right vestibular schwannoma. Preoperative bone window computed tomographic scans showed bone defects in the IAC posterior wall, which ran farther posteroinferiorly in the petrous bone, reaching the medial part of the jugular bulb. The tumor was accessed via a lateral suboccipital approach. There was no other major vein in the cerebellomedullary cistern, except for the vein running from the brain stem to the IAC posterior wall. To avoid complications due to venous congestion, the authors did not drill out the IAC posterior wall or remove the tumor in the IAC. LESSONS Several aberrant veins in the petrous bone are primitive head sinus remnants. Although rare, their surgical implication is critical in patients with vestibular schwannomas.

Decision making for the surgical approach of posterior petrous bone meningiomas

2011 ◽  
Vol 30 (5) ◽  
pp. E14 ◽  
Author(s):  
Pierre-Hugues Roche ◽  
Vincent Lubrano ◽  
Rémy Noudel ◽  
Anthony Melot ◽  
Jean Régis
Keyword(s):  
Cranial Nerves ◽  
Internal Auditory Canal ◽  
Case Series ◽  
Postoperative Mortality ◽  
Type A ◽  
Petrous Bone ◽  
Retrosigmoid Approach ◽  
Tumor Diameter ◽  
Dural Attachment ◽  
Anterior Petrosectomy

Object The authors undertook this study to examine the surgical approaches used to treat posterior petrous bone meningiomas at a single institution and retrospectively evaluate their surgical strategy based on a previously published classification. Methods Cases in which craniotomies were performed to treat posterior petrous bone meningiomas between 2002 and 2010 were retrospectively reviewed. Data were examined from 57 patients who were treated for 59 tumors. The tumors were classified into 3 types according to the location of their primary dural attachment: Type A, located around the porus trigeminus (33 tumors); Type M, located at the level of the porus of the internal auditory canal (IAC) (12 tumors); and Type P, located laterally to the IAC (14 tumors). The median tumor diameter was 34 mm (range 20–67 mm). Results The choice of the approach was based on tumor location, as the displacement of vascular structures and cranial nerves was primarily determined by the site of dural attachment on the posterior petrous bone. An anterior petrosectomy was performed in 82% of Type A meningiomas, and a retrosigmoid approach was used in 86% of Type P meningiomas. The spectrum of approaches was less uniform for Type M meningiomas. Overall, total resection was obtained in 39% of all cases, and in 18%, 50%, and 86% of Type A, Type M, and Type P tumors, respectively. The postoperative mortality rate was 8.8% (5 deaths among 57 patients), and all 5 patients who died during the early postoperative period had large Type A tumors. At last follow-up, the functional preservation of the facial nerve was excellent in 49 (94%) of the 52 surviving patients. Conclusions The authors believe that proper selection of the approach favorably impacts functional outcome in patients undergoing surgery for the treatment of skull base tumors. In the authors' case series of posterior petrous bone meningiomas, Type P and most Type M tumors were safely managed through a regular retrosigmoid approach, whereas Type A tumors were optimally treated via an epidural anterior petrosectomy.

scholarly journals Quantitative analysis of the surgical exposure and surgical freedom between transcranial and transorbital endoscopic anterior petrosectomies to the posterior fossa

2019 ◽  
Vol 131 (2) ◽  
pp. 569-577 ◽  
Author(s):  
Raywat Noiphithak ◽  
Juan C. Yanez-Siller ◽  
Juan Manuel Revuelta Barbero ◽  
Bradley A. Otto ◽  
Ricardo L. Carrau ◽  
...  
Keyword(s):  
Posterior Fossa ◽  
Additional Benefit ◽  
Range Of Movement ◽  
Statistical Comparison ◽  
Anterior Transpetrosal Approach ◽  
Surgical Exposure ◽  
Orbital Wall ◽  
Anterior Petrosectomy ◽  
Surgical Corridor ◽  
Orbital Rim

OBJECTThis study proposes a variation of the transorbital endoscopic approach (TOEA) that uses the lateral orbit as the primary surgical corridor, in a minimally invasive fashion, for the posterior fossa (PF) access. The versatility of this technique was quantitatively analyzed in comparison with the anterior transpetrosal approach (ATPA), which is commonly used for managing lesions in the PF.METHODSAnatomical dissections were carried out in 5 latex-injected human cadaveric heads (10 sides). During dissection, the PF was first accessed by TOEAs through the anterior petrosectomy, both with and without lateral orbital rim osteotomies (herein referred as the lateral transorbital approach [LTOA] and the lateral orbital wall approach [LOWA], respectively). ATPAs were performed following the orbital approaches. The stereotactic measurements of the area of exposure, surgical freedom, and angles of attack to 5 anatomical targets were obtained for statistical comparison by the neuronavigator.RESULTSThe LTOA provided the smallest area of exposure (1.51 ± 0.5 cm2, p = 0.07), while areas of exposure were similar between LOWA and ATPA (1.99 ± 0.7 cm2 and 2.01 ± 1.0 cm2, respectively; p = 0.99). ATPA had the largest surgical freedom, whereas that of LTOA was the most restricted. Similarly, for all targets, the vertical and horizontal angles of attack achieved with ATPA were significantly broader than those achieved with LTOA. However, in LOWA, the removal of the lateral orbital rim allowed a broader range of movement in the horizontal plane, thus granting a similar horizontal angle for 3 of the 5 targets in comparison with ATPA.CONCLUSIONSThe TOEAs using the lateral orbital corridor for PF access are feasible techniques that may provide a comparable surgical exposure to the ATPA. Furthermore, the removal of the orbital rim showed an additional benefit in an enhancement of the surgical maneuverability in the PF.

Custom-tailored transdural anterior transpetrosal approach to ventral pons and retroclival regions

2006 ◽  
Vol 104 (1) ◽  
pp. 38-46 ◽  
Author(s):  
Hans-Jakob Steiger ◽  
Daniel Hänggi ◽  
Walter Stummer ◽  
Peter A. Winkler
Keyword(s):  
Carotid Artery ◽  
Cranial Nerves ◽  
Extent Of Resection ◽  
Venous Congestion ◽  
Petrous Apex ◽  
Anterior Transpetrosal Approach ◽  
Target Field ◽  
Custom Made ◽  
Anterior Petrosectomy ◽  
Spinal Catheter

Object The extradural anterior petrosectomy approach to the pons and midbasilar artery (mid-BA) has the main disadvantage that the extent of resection of the petrous apex cannot be as minimal as desired given that the surgical target field is not visible during bone removal. Unnecessary or excessive drilling poses the risk of injury to the internal carotid artery, vestibulocochlear organ, and seventh and eighth cranial nerves. The use of a custom-tailored transdural anterior transpetrosal approach can potentially avoid these pitfalls. Methods A technique for a transdural anterior petrosectomy was developed in the operating theater and anatomy laboratory. Following a subtemporal craniotomy and basal opening of the dura mater, the vein of Labbé is first identified and protected. Cerebrospinal fluid ([CSF] 50–100 ml) is drained via a spinal catheter. The tent is incised behind the entrance of the trochlear nerve toward the superior petrosal sinus (SPS), which is coagulated and divided. The dura is stripped from the petrous pyramid. Drilling starts at the petrous ridge and proceeds laterally and ventrally. The trigeminal nerve is unroofed. The internal acoustic meatus is identified and drilling is continued laterally as needed. The bone of the Kawase triangle toward the clivus can be removed down to the inferior petrosal sinus if necessary. Anterior exposure can be extended to the carotid artery if required. It is only exceptionally necessary to follow the greater superior petrosal nerve toward the geniculate ganglion and to expose the length of the internal acoustic canal. The modified transdural anterior petrosectomy exposure has been used in nine patients—two with a mid-BA aneurysm, two with a dural arteriovenous fistula, one with a pontine glioma, three with a pontine cavernoma, and one with a pontine abscess. In one patient with a mid-BA aneurysm, subcutaneous CSF collection occurred during the postoperative period. No CSF fistula or approach-related cranial nerve deficit developed in any of these patients. There was no retraction injury or venous congestion of the temporal lobe nor any venous congestion due to the obliteration of the SPS or the petrosal vein. Conclusions The custom-made transdural anterior petrosectomy appears to be a feasible alternative to the formal extradural approach.

Maturation of the anterior petrous apex: surgical relevance for performance of the middle fossa transpetrosal approach in pediatric patients

2021 ◽  
pp. 1-7
Author(s):  
Robert C. Rennert ◽  
Michael G. Brandel ◽  
Jeffrey A. Steinberg ◽  
David D. Gonda ◽  
Rick A. Friedman ◽  
...  
Keyword(s):  
Pediatric Patients ◽  
Internal Carotid ◽  
Age Groups ◽  
Internal Auditory Canal ◽  
Petrous Bone ◽  
Growth Patterns ◽  
Ct Scans ◽  
Petrous Apex ◽  
Middle Fossa ◽  
Region Growth

OBJECTIVE The middle fossa transpetrosal approach to the petroclival and posterior cavernous sinus regions includes removal of the anterior petrous apex (APA), an area well studied in adults but not in children. To this end, the authors performed a morphometric analysis of the APA region during pediatric maturation. METHODS Measurements of the distance from the clivus to the internal auditory canal (IAC; C-IAC), the distance of the petrous segment of the internal carotid artery (petrous carotid; PC) to the mesial petrous bone (MPB; PC-MPB), the distance of the PC to the mesial petrous apex (MPA; PC-MPA), and the IAC depth from the middle fossa floor (IAC-D) were made on thin-cut CT scans from 60 patients (distributed across ages 0–3, 4–7, 8–11, 12–15, 16–18, and > 18 years). The APA volume was calculated as a cylinder using C-IAC (length) and PC-MPB (diameter). APA pneumatization was noted. Data were analyzed by laterality, sex, and age. RESULTS APA parameters did not differ by laterality or sex. APA pneumatization was seen on 20 of 60 scans (33.3%) in patients ≥ 4 years. The majority of the APA region growth occurred by ages 8–11 years, with PC-MPA and PC-MPB increasing 15.9% (from 9.4 to 10.9 mm, p = 0.08) and 23.5% (from 8.9 to 11.0 mm, p < 0.01) between ages 0–3 and 8–11 years, and C-IAC increasing 20.7% (from 13.0 to 15.7 mm, p < 0.01) between ages 0–3 and 4–7 years. APA volume increased 79.6% from ages 0–3 to 8–11 years (from 834.3 to 1499.2 mm3, p < 0.01). None of these parameters displayed further significant growth. Finally, IAC-D increased 51.1% (from 4.3 to 6.5 mm, p < 0.01) between ages 0–3 and adult, without significant differences between successive age groups. CONCLUSIONS APA development is largely complete by the ages of 8–11 years. Knowledge of APA growth patterns may aid approach selection and APA removal in pediatric patients.

scholarly journals The epitrigeminal approach to the brainstem

2018 ◽  
Vol 128 (5) ◽  
pp. 1512-1521 ◽  
Author(s):  
Georgios Andrea Zenonos ◽  
David Fernandes-Cabral ◽  
Maximiliano Nunez ◽  
Stefan Lieber ◽  
Juan Carlos Fernandez-Miranda ◽  
...  
Keyword(s):  
Cavernous Malformation ◽  
Anatomical Study ◽  
Normal Subjects ◽  
Surgical Approaches ◽  
Illustrative Case ◽  
Fiber Tractography ◽  
High Definition ◽  
Entry Zone ◽  
Corticospinal Tracts ◽  
Direct Distance

OBJECTIVESurgical approaches to the ventrolateral pons pose a significant challenge. In this report, the authors describe a safe entry zone to the brainstem located just above the trigeminal entry zone which they refer to as the “epitrigeminal entry zone.”METHODSThe approach is presented in the context of an illustrative case of a cavernous malformation and is compared with the other commonly described approaches to the ventrolateral pons. The anatomical nuances were analyzed in detail with the aid of surgical images and video, anatomical dissections, and high-definition fiber tractography (HDFT). In addition, using the HDFT maps obtained in 77 normal subjects (154 sides), the authors performed a detailed anatomical study of the surgically relevant distances between the trigeminal entry zone and the corticospinal tracts.RESULTSThe patient treated with this approach had a complete resection of his cavernous malformation, and improvement of his symptoms. With regard to the HDFT anatomical study, the average direct distance of the corticospinal tracts from the trigeminal entry zone was 12.6 mm (range 8.7–17 mm). The average vertical distance was 3.6 mm (range −2.3 to 8.7 mm). The mean distances did not differ significantly from side to side, or across any of the groups studied (right-handed, left-handed, and ambidextrous).CONCLUSIONSThe epitrigeminal entry zone to the brainstem appears to be safe and effective for treating intrinsic ventrolateral pontine pathological entities. A possible advantage of this approach is increased versatility in the rostrocaudal axis, providing access both above and below the trigeminal nerve. Familiarity with the subtemporal transtentorial approach, and the reliable surgical landmark of the trigeminal entry zone, should make this a straightforward approach.

scholarly journals Anatomy of the Orbit

2020 ◽  
Vol 81 (04) ◽  
pp. 319-332
Author(s):  
Stefan Lieber ◽  
Juan C. Fernandez-Miranda
Keyword(s):  
Anterior Part ◽  
Cranial Base ◽  
Surgical Approaches ◽  
Microsurgical Anatomy ◽  
Orbital Apex ◽  
Special Issue ◽  
Superior Orbital Fissure ◽  
Anatomical Structures ◽  
Transnasal Surgery ◽  
Maxillary Sinuses

AbstractThe orbit is a paired, transversely oval, and cone-shaped osseous cavity bounded and formed by the anterior and middle cranial base as well as the viscerocranium. Its main contents are the anterior part of the visual system, globe and optic nerve, and the associated neural, vascular, muscular, glandular, and ligamentous structures required for oculomotion, lacrimation, accommodation, and sensation.A complex stream of afferent and efferent information passes through the orbit, which necessitates a direct communication with the anterior and middle cranial fossae, the pterygopalatine and infratemporal fossae, as well as the aerated adjacent frontal, sphenoidal, and maxillary sinuses and the nasal cavity.This article provides a detailed illustration and description of the microsurgical anatomy of the orbit, with a focus on the intrinsically complex spatial relationships around the annular tendon and the superior orbital fissure, the transition from cavernous sinus to the orbital apex. Sparse reference will be made to surgical approaches, their indications or limitations, since they are addressed elsewhere in this special issue. Instead, an attempt has been made to highlight anatomical structures and elucidate concepts most relevant to safe and effective transcranial, transfacial, transorbital, or transnasal surgery of orbital, periorbital, and skull base pathologies.

Key aspects of anatomy, surgical approaches and clinical examination of the hand

2019 ◽  
Vol 33 (1) ◽  
pp. 1-13 ◽  
Author(s):  
Ashley W. Newton ◽  
Xenia N. Tonge ◽  
David H. Hawkes ◽  
Vijay Bhalaik
Keyword(s):  
Clinical Examination ◽  
Surgical Approaches ◽  
Key Aspects

scholarly journals Primary meningeal melanoma masquerading as neurofibromatosis type 2: illustrative case

2021 ◽  
Vol 2 (20) ◽  
Author(s):  
Melanie Lang-Orsini ◽  
Julian Wu ◽  
Carl B. Heilman ◽  
Alina Kravtsova ◽  
Gene Weinstein ◽  
...  
Keyword(s):  
Internal Auditory Canal ◽  
Primary Melanoma ◽  
Neurofibromatosis Type ◽  
Neurofibromatosis Type 2 ◽  
Proliferation Index ◽  
Illustrative Case ◽  
Radiographic Findings ◽  
Peripheral Nerve Sheath Tumors ◽  
Spinal Lesion

BACKGROUND Primary meningeal melanocytic neoplasms are exceedingly rare tumors, representing only 0.06% to 0.1% of all primary brain tumors and ranging in spectrum from benign localized tumors to highly aggressive malignant lesions. The diagnosis of these tumors is often challenging from clinical, radiological, and pathologic standpoints. Equally challenging is the distinction between primary meningeal melanocytic neoplasm and metastatic melanoma. OBSERVATIONS The authors reported the case of a 41-year-old man with imaging findings diagnostic of neurofibromatosis type 2: bilateral internal auditory canal lesions (most consistent with bilateral vestibular schwannomas), two dura-based lesions presumed to be meningiomas, multiple spinal lesions consistent with peripheral nerve sheath tumors, and one intramedullary spinal lesion consistent with an ependymoma. Biopsy of these lesions revealed melanocytic neoplasms with mild to moderate atypia and a mildly elevated proliferation index, which made the distinction between benign and malignant challenging. In addition, the disseminated nature of these tumors made it difficult to determinate whether they arose from the meninges or represented metastases from an occult primary melanoma. LESSONS This case illustrated the challenges presented by the diagnosis of meningeal melanocytic neoplasms and highlighted the importance of integrating the clinical and radiographic findings with histologic appearance and molecular studies.

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